This invention relates to prolonging the life of refractory brick walls, and more particularly to a method of straightening collapsed portions of the flue walls of a carbon anode ring furnace.
In the process of aluminum reduction, carbon anodes are used in the reduction process. These carbon anodes are generally formed by compacting a calcined petroleum coke aggregate and a pitch binder into a self-supporting block which is subsequently heat-treated in a large ring furnace. The ring furnace includes a number of flues each comprising a pair of spaced vertical walls constructed of refractory brick formed of silicon carbide or the like. Extending between the confronting surfaces of the walls of the flue are a number of baffles also constructed of refractory brick. These baffles direct the flow of a combustible gas mixture in a predetermined path through the flue. Temperatures as high as 1300.degree. C. exist in the hotter areas of the flue, for example, adjacent the upper portion thereof at the point of introduction of the combustible gas mixture. After operation of the furnace for a number of cycles over a period of time at such high temperatures, portions of the flue walls frequently collapse inwardly, particularly in the "hot spots" adjacent the gas inlets where the walls are generally unsupported by the baffles. Such wall collapses undesirably reduce the cross-sectional area of the gas flow path which, in turn, considerably reduces the efficiency of the furnace. Ultimately, of course, the entire flue walls must be torn down and replaced at considerable expense in terms of both material and labor costs. Moreover, operational efficiency of the aluminum reduction facility as a whole can be impaired by frequent furnace shutdowns for replacement of the collapsed flue walls.